All the small things
by Taisi
Summary: An experiment gone wrong de-aged Donnie back into a toddler. Good thing Mikey's great with kids.
1. all the small things

A/N: Writing this for funsies, and also because little Don is just so cute and the B Team pair is my ultimate weakness. :p It'll probably be a few chapters long!

* * *

Mikey let out an _oof_ when Donnie abruptly jumped into his lap, one arm coming up automatically to catch the much smaller turtle before he could fall. The kid was in full Worm Mode, squirming and resituating until he had himself tucked neatly under Mikey's chin, both his little arms wrapped tight around something he was hugging protectively to his chest.

Good thing Mikey had a shell, or he'd be more black and blue than he was green by the time this whole turtlesitting thing was over.

Off somewhere in the distance—he could hear it plain as day, now that he was listening—Raph and Leo were arguing in their _"outside voices,"_ using a few words in particular that would have curled sensei's whiskers. Mikey grinned.

"Ooh, I bet _someone_ got into something they shouldn't have," he teased, poking Donnie playfully in the soft cartilage of his side. "What was it this time? Was it Raph's sais again? You know he just got those cleaned up from last time."

"It wasn't Raph's sais," Donnie mumbled. After a minute, he lifted his head and hit Mikey with those big brown eyes, and Mikey's whole heart just melted right there on the spot. "If I show you, you won't get mad, right, Mike? You promise?"

He could pretty much ask for the moon and Mikey would be like _sure, absolutely._ "I promise, dude."

That was all it took for Donnie to unfold his arms and show Mikey his prize—the dismantled mess of gizmos and wires and plastic casing that might once have been their secondhand toaster. Mikey bit the inside of his lip to keep from laughing, and only because Donnie's expression was so solemn and sincere.

"I just wanted to see how it worked," he said, totally disheartened. "I didn't mean to make Leo and Raph so mad. And I didn't mean to set the counter on fire."

Okay, the faraway shouting and commotion made a lot more sense now. Mikey gave the super-long purple tails of Donnie's mask a gentle tug. "Dee, you gotta get permission before you take stuff apart," he said seriously. "I don't care about the counter, or even the whole kitchen, but that fire could have hurt you, and then what would I do?"

Just the thought of it was kind of horrifying, and he did a quick once-over of his brother to make sure there were no new "boo-boos" anywhere on his little person. Donnie's head hung even lower at Mikey's mild reprimand. "Sorry."

 _Aww, Dee._

It was so hard to scold him for this kind of stuff, and not just because Mikey was terrible at the scolding thing to begin with. This kind of stuff was different, because Donnie wasn't getting into trouble to be ornery, he was just _curious._

All the mishaps and dissected TV remotes—and, okay, the occasional fire—were just sort of the Donatello version of building blocks and ABCs. Mikey knew how smart Donnie was, way better than he did back when they were both little, and he knew that the broken toaster in Donnie's lap would be put back together _better_ by the end of the week, without any instruction manuals or Google searches. Wasn't that kind of amazing?How was Mikey supposed to yell at him for that?

So Mikey hugged him instead, squeezing him until he squeaked a little. "I know you're sorry, buddy. It's okay as long as you didn't get hurt."

Donnie's little hands found his quickly, curling their fingers together. "I didn't get hurt. Leo dumped the soup on the fire before it could get big."

"Wait, he what? The whole pot?" Donnie nodded, and Mikey groaned. "But that was lunch!"

"You're complainin' about _lunch?"_ There was Raph, looking pretty ruffled and thoroughly ticked off as he stormed over with a dirtied cleaning rag in hand. Donnie ducked back around his dismantled toaster, blinking owlishly at their red-banded brother from the safe circle of Mikey's arms _._ "You— I can't believe this. You're lettin' him get away with setting the _kitchen_ on fire?"

"Oh, get over it," Mikey retorted with a roll of his eyes. "You've probably done way worse than that trying to make breakfast."

Raphael spluttered indignantly. "That's not the point! He needs to find safer stuff to play with!"

"By safe he means _boring,"_ Donnie mumbled, and Mikey rubbed his head.

He had a new appreciation for how hard it must have been on Master Splinter the first time they were growing up. Donnie kind of deserved whole libraries and laboratories and spaceships, he maybe deserved the entire world—and the best his family could give him was someone else's trash. Junkyard finds, dirty books and worn tools and broken things. It sucked.

"April promised she'd bring some of her school stuff for him this weekend," Mikey said, meeting Raph scowl for scowl in a way he never would have a week ago. "Until then, we're probably gonna lose a few things. And you can deal with it, 'cause whatever it is, Donnie's probably the one who built it in the first place."

Raph stared at him without speaking for a minute, and then his eyes fell to Donatello. The accident in the lab had happened nearly a week ago, and Raph hadn't warmed up to the new Don at _all._

"He'll come around," was all Leo had to say on the subject. "And Rockwell says he can fix it. Don't worry."

So, fine. Mikey wasn't worried. But as Raph shook his head and turned away without another word, Mikey glared at the back of his shell.

"Jerk," he said, and didn't care if Raph heard him or not. Donnie was their brother, whether he was six years old or sixty, and treating him like a stranger was pretty much the worst. He heard a soft sound like a sniff from the little ball of turtle in his lap, and a good ninety percent of his irritation floated away like a plume of smoke. "Oh, you better not be crying, Donnie. What'd I tell you about crying?"

"If I do it, you'll do it, too," Donnie recited promptly, and his eyes were a little suspiciously wet when he looked up, but his face was dry, and there was a smile tugging at the corners of his mouth. "Thanks, Mike. And sorry about the soup."

"Not your fault, dude. Leo tends to panic around fire."

"Guess that means we have to order pizza, huh?" Donnie asked innocently. Mikey grinned outright at him.

"Tell you what, buddy," he said, bundling Donnie (and his toaster) up a little closer and rubbing their foreheads together. "I'm gonna miss you when you get big again, and go back to being too busy for me."

Donnie giggled at him, all soft and sweet.

"Don't be silly. You're the coolest brother _ever!_ I'm _never_ gonna be too busy for you."


	2. true care truth brings

"Fix your feet, Dee. If you're not balanced just right, you'll tip over like a soda can."

Mikey proved it by giving his brother's shoulder a little push, and sending him stumbling sideways a few steps. Donnie's face screwed up in frustration—he'd been redoing that kata for close to twenty minutes and was no closer to getting it right than when he started _._ He wasn't _used_ to failure, and if Mikey remembered their childhood as clearly as he thought he did, Don's tantrums had only ever been second to Raphael's.

Quickly, Mikey straightened from his crouch and got into position beside him before any hell had chance to break loose. "Look, like me, Donnie. We'll try it together, okay?"

Donnie's scowl didn't _totally_ disappear, but he followed Mikey's lead and the grumpy outburst no longer seemed impending. _Score._

Mikey's practice was actually already over for the day, but Donnie was training separately from them for as long as he was shrunk-ified. Even though Leo and Raph had already vacated the dojo in favor of an horror movie marathon, and even though there was a pile of comic books on Mikey's bed with his name all over it, a la Casey, Mikey had decided to stick around.

"Okay," he said once Don was ready. "Imagine your legs are tree trunks. And no one can tip one of those over, right? You need, like, a bulldozer to move a tree." Splinter's whiskers twitched in what was probably an amused smile, but he didn't interrupt; and Donnnie's eyes were wide and attentive as he stood there soaking up all of Mikey's words like a little green sponge. "You know _why_ those trees are so tough?"

"Roots?" Donnie said, and smiled when Mikey gave him two thumbs up.

"You got it! They have a bunch of roots that go way deep underground and keep them steady. That's what your feet do, buddy." Mikey took the next step of the kata and planted his foot firmly, waiting for Donnie to mirror the move before he added, "And that way when someone tries to roll you in a fight, it's like they're running into a brick wall."

Don lost his balance in the third step, and tripped when one of the tails of his mask got caught underfoot, and Mikey braced himself for the nuclear fallout.

Instead, incredibly, his brother screwed his face up and doggedly started over again from the beginning, mimicking Mikey's pose. Extra slow and careful, this time, but each step was right on the money. And the last kick was a little shaky, but his landing was solid, and he maintained that last pose for a long moment of stunned stillness.

Then he looked up at Mikey and _grinned,_ thrilled and excited and so happy he shone with it.

"I did it!"

"I saw! That was so cool!" Way cooler than movie marathons and comic books _combined_. He slapped Donnie a double high-five, then grabbed him around the middle and lifted him up as high as he could. It made Don laugh, high-pitched and delighted, his little hands pawing at Mikey's bigger ones. "Time to celebrate. I'm gonna make you a banana split as big as your _head_."

* * *

Practice was one thing, real life was another—and their first patrol since the accident turned out to be kind of brutal. They weren't used to fighting as a three-man team, and Mikey kept automatically adjusting for Donatello, leaving one side of their tight formation wide open, before his brain could catch up to his body and remind him Donnie wasn't a part of the equation anymore.

So, yeah. He kind of took a pounding from Rahzar before Raph managed to fight off his gaggle of Footbots and save his shell. They turned it around there at the end, and the Purple Dragons didn't get away with their truck full of stolen goodies, but _yikes,_ was Mikey sore all over.

From the worried looks Raph and Leo were giving him, he probably looked as bad as he felt. But he managed to get out of the Party Wagon and out of the tunnel on his own steam, tipping awkwardly over the turnstiles and hobbling like an old person past the pit and toward the bathroom.

Normally they got patched up by Doctor Dee, in his lab-slash-garage-slash-hospital, but this time Mikey would have to make do with their secondary first aid kit and his own, unrivaled skills at bandaiding.

Or not. Raph turned him by the shoulders toward the sunken part of the living room, pointed silently at one of the seats with that _"sit down or I will_ add _to your bruises"_ expression Mikey knew so well, and stalked off probably to get the kit himself.

"Mike?"

Glancing up, Mikey felt his face split in an automatic grin. "Hey, Dee! Did you have fun with sensei while we were gone?"

Donnie's eyes were huge and moonlike, staring at Mikey like he'd never seen him before. _Why is he looking at me like—oh, crap._ Leo leaped on his chance to mother hen, tucking an arm around the top of Mikey's carapace and helping him down into the pit—which, okay, he probably wouldn't have made it down on his own—while Mikey did his best to make the bruises disappear by sheer willpower.

They didn't.

"You got hurt," Donnie whispered, sounding like he was about to cry. Cowardly Leonardo said something about letting sensei know they were home, and left Mikey to handle the tears. Way to hero, Leo.

"It's nothing some Neosporin can't make all better," he said, and opened his arms in as much invitation as Donnie needed to cross the room at a sprint. Mikey was braced for impact, but Donnie stopped short of jumping into his lap the way he usually did, and picked his way up very carefully instead. He got settled in record time, and nuzzled as close as he dared when Mikey wrapped him in a warm hug. "I'm okay, buddy. Promise."

The P-word usually worked like a charm. After a long minute, as Raphael returned with the first aid kit under his arm, Donatello mumbled, "Okay."

* * *

Donnie crawled into bed with him that night. Mikey totally saw that coming.

He was pretty much a Jedi in the ways of little brothers, all things considered, and he lifted up one side of the quilt for Donnie to scoot under. Don did a little worming around to get comfortable, and rather than tucking himself up against Mikey's plastron, right under his chin, like he usually did, he settled instead with his head on the pillow and his round eyes level with Mikey's.

"Are you okay?" he whispered softly, face creased at the corners with a worry much older than he was. Mikey felt his whole heart swell with something warm and tender, and he reached over with one arm to tug his little big brother a bit closer.

"Yeah, Dee, I'm okay."

He wasn't expecting Don to reach out and cup the unmarked side of his face in one small hand, looking grave and determined and all of six years old. "I'll practice ninja really hard, and get really strong," came his quiet promise, "and then I'll protect you."

Even with his clock turned back close to ten years, and no memory of those years he lost, Donatello was still Donatello. Mikey scooted over closer and wrapped him up in both arms this time, pressing a kiss to the top of his short, round beak.

"You always do," Mikey told him, loving him so hard it hurt. "Is it okay if I protect you back?"

"Yeah," Donnie replied, muffled against Mikey's shoulder. His fingers were tangled in the mask Mikey had left hanging loosely around his neck, and for the first time all night he sounded close to a smile. "We can protect each other."

"Deal." Mikey rubbed his tiny carapace with gentle fingers, something he vaguely remembered Leo doing when Mikey was sick a bunch of years ago. After a few minutes, Donnie's body fell loose-limbed and heavy with sleep, but Mikey stayed up for a little while longer, counting the cracks in the wall and listening to his brother breathe.

It was pretty dumb, but for some reason Mikey was afraid to let him go.


	3. I'll take one lift

At first Mikey wasn't sure what woke him up. His face pulled into an automatic wince about two seconds into his new consciousness as the aches and pains of yesterday made themselves known with drums and symbols, and then Mikey blinked a few times as he adjusted to the soreness.

 _Ow._

A moment later Leonardo was leaning over him; all warm blue eyes and crooked smile.

"Morning, Mikey," he whispered, smoothing a gentle hand over his forehead. "How are you feeling?"

Ah, yes. The customary morning after a beating checkup, a la Leo. Sometimes his brothers were so predictable it was downright silly. Mustering up a smile, Mikey started to shift upright, propping himself up on an elbow. But then Leo's whispering made a lot more sense, ditto the way Leo's hand grew heavier on him to keep him still before he could make it all the way up—because Donnie was still asleep right next to him, a tiny little ball of dreaming turtle. And he hadn't woken with Leo's silent entrance 'cause he was too young to have developed those weirdly intense, over-the-top ninja senses yet, but ninja babies were still way more sensitive than _non-_ ninja babies. Just that tiny amount of shifting around on Mikey's side of the bed was enough for Don to start shifting, too; mumbling something soft and sleep-broken, face wrinkling and oh, _man,_ he was a nightmare when he got woken up too early, that hadn't changed a bit.

Mikey froze in his tracks, sending Leo a panicked look, and it turned out Leo was a whole heck of a lot braver when Donnie wasn't awake. He grinned at whatever Mikey's face looked like, and then leaned over Donnie and extracted him from the pillow and blankets in one swift, expert move.

And Mikey sort of stared, because Leo's arm curled around Donnie the right way on the first try, it took Mikey like four tries to get it right, and his face was so open and affectionate that just looking at him felt like spying on something secret.

"Shhh, little brother," Leo said, in the exact same way he'd greeted Mikey with good morning moments ago. And Mikey's face flushed a little, 'cause it was the way Leo talked to him all the time, but he had no idea it sounded like that. It wasn't like, over-the-top gooey or sweet, it just… Mikey knew his brothers so well, they'd been his only friends and constant playmates and his whole entire world from ages 0-15, so he really _knew_ his brothers.

And Leo at his happiest was a quiet, unobtrusive thing—when Raph would shift over wordlessly and lean his head against Leo's shoulder, when bright-eyed Donnie would search Leo out to tell him all about a new gizmo, when it was just the two of them and Mikey stretched his arms out for a hug, no pranks attached.

And that was Leo now, when little Donnie sighed and settled down, nuzzling into the crook of Leo's neck and shoulder. His eyes flicked from Don to Mikey, and they were still warm, but newly amused as he took in Mikey's expression.

"Easy as pie," he whispered, and Mikey made a show of his silent applause. If it made Leo's sideways turn a little smug, well, that was okay.

"Dude, you've _gotta_ spill. What are you, a wizard? How did you know how to do that?"

Leo gestured, and Mikey scooted over, drawing his legs in tailor-style as Leo sat on the edge of the bed next to him with Donnie sleeping soundly in the cradle of his hardened arms. "You guys all used to crawl into bed with me all the time," his big brother said, with that same fondness still in his voice, and something melting in the blue of his eyes. "After a nightmare, or a scary movie, or a thunderstorm. I guess Donnie's at that age again."

Mikey remembered that. And he remembered that no matter what time it was, or how tired they'd been after exercises, or how annoying he'd been that day, Leo _always_ met him with warm arms, scooting over to make room for him and hushing him until he fell asleep again.

 _When did I get too old for that?_ That kind of sucked.

"I guess it just made sense to wake up and see you, huh?" Mikey smiled, giving Leo a playful nudge with his shoulder. "Maybe you should play babysitter from now on, you're the pro at big-brotherdom."

"You're doing a great job," Leo replied instantly, framing Mikey with one of those Leader Looks that always made his brothers go quiet and attentive on pure instinct or reflex. Then the look softened a tiny bit, and Leo added, "Sorry we haven't been much help."

"Yeah, uh—not that I mind having Donnie all to myself," Mikey began, gesturing vaguely with his hand, "but what's up with that? Like, you and Raph have been avoiding him like the plague."

Leo's eyes fall back to sleeping Donatello, and there was self-chagrin in his face now. Aw, man. After what felt like a year, he finally said, "He's just so _small_ now."

"Yeaahh," Mikey agreed, not really getting it. "He's small and adorable, and you're _ignoring_ him, when you should be taking all the pics and recording as many videos as you can, like me. Blackmail, yo." It made Leo snort, an amused grin stretching across his face, and they both took a minute to appreciate how annoyed Donnie was gonna be about that when he was back to the right age.

"I guess it's pretty stupid," Leo finally said, lifting a hand to smooth a finger over Donnie's forehead. "It's just that… He's just so _small_ now. And soft. And he cries so easily, and—"

"Oh," Mikey said, understanding. _"Oh."_

"I don't want to hurt him," Leo continued lamely, looking anywhere but at Mikey. "I think Raph's the same way. We've always played kinda rough, ever since we were little—wrestling and tumbling and all that—but we've always been about the same size, and now… It'd be so easy to break his _bones_."

"Aw, Leo." Mikey couldn't help grinning at him—of _course_ it'd be something like this, Mikey should have guessed as much from the very beginning. "You're such a dork, holy wow. You don't have to _spar_ with Donnie to spend time with him, or even get all rambunctious with him like I do—just, like, read one of his books to him, or color pictures, or watch T.V. We always competed for your attention back in the day, you know? Don would go _bananas_ to have you all to himself."

Ooooo-kay, that last thing had kinda slipped out under the radar. Yikes. Leo was staring at him, and Mikey forced a laugh and added, "So, yeah," but nope, the conversation wasn't going anywhere, it had officially stalled, and _dangit,_ if Leo made this awkward Mikey was going to take away his Donnie privileges, just you watch—

But all Leo said, quietly, was "I didn't know that." He lifted the arm that wasn't curled around Donnie, and Mikey cottoned on pretty quickly—ignoring the hurts and bruises and scooting over to be tucked against Leo's side. "I'm pretty clueless, huh?"

"Maybe, a little," Mikey said honestly. "But if you weren't a little clueless you'd be right next to perfect, and then you'd be impossible to live with."

"Good thing I've got you three to keep me humble," Leonardo said wryly, and Mikey giggled. What were brothers for but knocking each other down a peg when they needed it? It kind of went hand in hand with lifting each other up over clouds and stars, and it came as easily to the four of them as breathing. "So what are we gonna do about Raph? This whole thing's made him kind of miserable."

"Actually," Mikey said, with a wink that made Leo roll his eyes, "I have a plan."

It was Saturday, which meant two things. One, no training for the day. Two, Raph was almost guaranteed to be in front of the T.V. watching cartoons.

He looked up as his brothers came in, and Mikey watched something painful happen to his eyes as he took in the three of them, and Leo holding Donnie—something like hurt at the perceived exclusion, something super honest and open for just a split second before it was gone again, covered up by a scowl as his eyes dropped back to the television.

"Y'look like crap, Mikey," he said, gruffly. Mikey shared a quick look with Leo. Go time.

"I feel okay, though," he said brightly. "I was gonna make French toast for breakfast—sound good?"

He could tell it was the last thing Raph was expecting, from the way his eyes flicked up again. It was his favorite, as far as breakfast went, and he knew Mikey knew it, too. "Guess so."

"Cool! And Leo wants to learn how to make it, so we're gonna leave Don here with you, 'kay?"

Leo was already moving, and Raph didn't have time to do more than look alarmed before he had a sudden armful of sleepy toddler. "What the—Leo, take him back!"

"C'mon, Raph, I really wanna do this," Leo said, arranging his face into something earnest and stubborn and just the right shade of imploring; Raph didn't stand a chance. C _ritical hit,_ Mikey though victoriously, when ninety percent of the ire in their hot-tempered sibling's face bled out. But the plan was to make the whole thing quick, like a ripping off a bandaid, so Mikey reached out to tug insistently on Leo's arm. Leo let himself be pulled back a step, and added like he couldn't help it, "Just for a little while, okay?"

"But—but—" Raph's hands were held up and away from Donnie, like the kid was poisonous—or, Mikey amended fairly, like he was something really delicate that Raphael didn't want to break. "What do I do when he wakes up?"

"You'll be okay, bro," Mikey told him—and maybe it was 'cause he looked all banged up and bruised that Raph didn't argue with him. Or maybe 'cause he really wasn't actually as opposed to spending time with Don as he wanted everyone to think he was. Whichever one it was, it gave Mikey and Leo time to escape to the kitchen.

"I feel bad," Leo said predictably two seconds later, and Mikey patted his hand.

"You're both idiots," he said reassuringly. "Don's not a rubik's cube, dude. He's a little kid, and literally all he wants to do is play with you."

Leo reached for the eggs, and Mikey handed them over. Okay, so Leo didn't actually _have_ to help Mikey make French toast, it had been a tiny little white lie to leave Raph alone with Donnie, but… some things never changed, and Mikey was warmed all the way down to his bones at the prospect of getting some one-on-one time with his oldest brother.

They were dipping bread when Leo spoke up again, flecked with cinnamon and egg batter; "You think its working?"

And Mikey didn't answer by way of words—just left a slice of bread to drown and led the way to the kitchen doorway, pulling back the curtains and gesturing widely for Leo to observe.

Donnie was wide awake, sitting in Raph's lap with the bigger turtle's arms draped comfortably around his shoulders. They were watching what sounded like Power Rangers, and Donnie was chattering at about a mile a minute, his head tipped back so he could look up at Raph while he did; and Raph's eyes were the warmest green in probably the whole entire universe, his fingers curled around Donnie's little hands—and he wasn't smiling, but he was so happy it looked like it hurt.


	4. your ride best trip

The day Rockwell finished the antidote (or whatever), Casey brought Donnie a little toy car. It was remote-controlled, and battery-powered, and Donnie's eyes were the brightest thing in the whole universe when their human friend knelt down to show him the controller. It was cute, but mostly it was to keep him busy while Rockwell and April set up the lab—putting the scene of the accident back together, down to the last broken beaker, and getting all the new chemicals ready.

The whole thing kind of reminded Mikey of the Kid Flash origin story, Barry Allen recreating the lab accident that gave him super powers for his girlfriend's nephew, and _whoops_ , who knew lightning would strike the same place twice and give lucky little Wally West a tap into the Speed Force?

April assured him there would be no lightning involved in Donnie's case. Which was good, 'cause comic books made it pretty clear that lightning _hurt._

"Mike," Donnie called from the other side of the room, smiling ear to ear. "Mike, come play with me!"

 _Man,_ Mikey was gonna miss that. And he was gonna miss the way Donnie put his arms out to be picked up, and the way he'd giggle behind his hand at all of Mikey's jokes, and sit on the counter to help him make lunch, and drink in everything he said like a wide-eyed little sponge.

But Mikey missed his big brother, too. So, since he was gonna miss him _either_ way—

"I'm comin', munchkin," he said with a sideways grin, hopping to his feet. And if the look his father gave him on his way by was a little _too_ knowing, a little _too_ understanding… well, whatever. Sensei always said he had a great imagination; Mikey was _really good_ at pretending.

And he could _totally_ pretend like this wasn't gonna hurt. He could pretend like it was okay when things went back to the way they used to be—when Donnie was more likely to slam a door in his face than ask to read comic books with him, or watch T.V., or make shadow puppets on the rice paper walls of the dojo. It wasn't right that this accident should change anything, or that he should _want_ it to. He loved Donnie no matter how big or little he was, he really, truly did.

This was a right to a wrong. This was a _fix._ So why was it twisting him up inside?

Raph and Leo mostly seemed relieved that the whole thing was finally over, when April opened the lab door and said they were ready. Raph rubbed Donnie's head fondly, and Leo hugged him tight around the shoulders, and sensei lifted him up to brush a kiss over the top of his head. Casey bumped Donnie's arm with a gentle fist, and told him he could keep the car, and then Donnie was putting out his hands, round eyes reaching for Mikey from not that far away, and Mikey reached over automatically to lift him out of sensei's arms and hug him tight.

"I'm a little scared," Donnie whispered, all sincere, and like they weren't standing right there in front of their whole family. He gazed up at Mikey with the whole world in his eyes, and Mikey swallowed a sudden lump in his throat and smiled back.

"Don't be scared, Dee. It'll be over before you know it, and then you'll be my big bro again. And you're so good at that!" Rockwell was shifting around impatiently, probably only keeping quiet under the indomitable force of April's laser-like glare, but it made Mikey a little self-conscious anyway—and the rest of everyone was staring at him, too, so he pressed a quick kiss between his little big brother's eyes and handed him over to April. Donnie's hands lingered on his arms, holding tight for another split second or two; looking too stricken and anxious for someone just about six years old. So Mikey put all his feelings on a shelf and locked them up, and gave Donnie a wink and a playful grin. "See you soon, dude. Promise."

It worked like a charm—always did—and Donnie was finally smiling back and letting go. April tucked him into her arms like a seasoned pro, and Mikey wasn't really expecting the kiss she pressed to his cheek, or the gentle nudge Raph gave his shoulder, and then the lab door was closing on little Donnie's little wave, and Mikey stood there just staring at it long and hard.

An arm slipped around him from one side, and he blinked, glancing up and over at Leonardo.

"You aren't losing him, Mikey," his big brother said, eyes all deep and soft. Mikey sort of flinched from them, and all their warm understanding, and shrugged one shoulder.

"Guess not."

He kinda was, though.

* * *

Donnie came out looking pale and weak on his feet, but he met them with a gap-toothed smile that sent Mikey's heart soaring, and he wasn't sure which of them moved first but they all piled onto Donnie at just about the same exact time, tumbling to the floor in an ecstatic turtle pile.

"We _missed_ you," Mikey said gleefully, and timed his hug to Raph's; pulling away when his red-banded brother did, smiling up at Donnie with honest warmth. If it were up to him, there would have definitely been _way_ more hugging—after all, he'd had to wait an _hour_ to see for himself that Donnie was okay, and it had been the longest hour of his _life_ —but big Donnie wasn't the cuddlebug little Donnie was, and Mikey wasn't going to be clingy and weird about this, he wasn't going to make things awkward between them. Instead he took a big step back, and spread his arms wide, and said, "We should celebrate!"

The idea was met with a roar of approval from Casey and Raph , while April went to grab the takeout menus off kitchen counter and Leo invited the Mutanimals to stay, and Donnie…just sorta stood there, looking at Mikey with the fading footprint of a smile on his face, and something hurting in his round brown eyes.

"Everything okay, Donnie?" Casey said quietly, with a worried wrinkle in his brow. Donnie blinked, eyes darting over to their human friend, and after a moment his grin bloomed back and that limping sadness from a moment ago was banished to somewhere far away, and Mikey could breathe easy.

"Yup," Donnie said softly, "everything goes back to normal, now."

* * *

Or, you know, almost.

Because two and a half weeks later, they were ambushed in some dark alley. Bebop took a cheap shot at Donnie, and Donnie fell three stories to the ground; and then Rocksteady was charging, and Raph and Leo were too far away, Donnie was still struggling to get his feet back under him, struggling to push himself upright—

Then he met Mikey's eyes in the dark, and distress turned to horror, and he screamed, "Mikey, _no!"_

But Mikey was moving already, before he made any conscious decision to— _not Donnie, not Donnie, please not him—_ reaching out with both hands and pushing Don as hard as he could out of harm's way.

Then there was crushing impact, like he was hit by a speeding truck or a subway train, and his brothers were yelling, and his head slammed into something solid, and he was gone.

* * *

Mikey woke up in the infirmary—knew it before he even knew he was awake, by the quiet hum of cooling fans and computers, the familiar smell of engine oil and hazelnut coffee—and it was such _instant_ comfort, always was. He hadn't been in here in weeks, not since the accident that made Donnie—

 _Donnie._

His next breath hitched in his throat, and hands came down on his arms a second later, before he could so much as open his eyes or work himself into a proper panic.

"Shhh, easy, Mikey, it's okay."

It was soothing and certain and totally disarming, and Mikey leaned into those hands before he knew what he was doing. He knew this place, and he knew that voice, and he knew the touch of those hardened, calloused fingers against his shoulders—knew all of it was good, all of it was safe. But— _Donnie._ Mikey had to be sure he was okay, had to _make_ sure, Donnie _needed_ him. His eyelids felt like sandbags as he struggled to get them open under weighted, clinging sleep; shell, even his _shell_ felt tired, and the soft-worn quilt draped over him might as well have been made of _lead,_ and those strong hands weren't budging for a second.

"What happened?" he asked, or thought he did—the words all ran together, kind of like his brain was starting to. He was only barely holding onto consciousness with both hands, here, but he'd _fight_ sleep tooth and nail because he _had to know—_ "Where's Donnie?" Mikey tried again, desperately. "Is he okay?"

"He'll be okay when _you_ are," came the quiet voice again, and Mikey didn't think he liked that answer. He pushed against the hands on his arms, and they only tightened there. "Mikey, _please."_

Well sorry, whoever, but he didn't have time to lay around and listen to weirdly elusive answers, he had a little big brother to find, and just as soon as he figured out how to make his limbs work again Mikey was outta here.

"Y'don't understand," he tried to explain, pawing uselessly at the hands that were planted like oak trees on his arms. "I gotta—I _gotta_ go, okay? Y'gotta let me go, he _needs_ me _._ "

"I know. I know," and that voice was still soft but sort of broken somewhere in the middle, tight around the edges and choked—like he was _crying,_ and Mikey didn't know much of anything right now, but he knew where he was, and he knew that voice and he knew those hands, and when he finally _finally_ managed to drag his eyes open, he knew the round brown eyes swimming inches from his own, knew them like he knew his own name.

"Donnie," he whispered, reaching with his fingers because he couldn't quite lift his arm, and Donnie sobbed—a tiny, hiccuping little sound—and snatched Mikey's hand up in both of his.

And Mikey didn't know hearts could break like this, out of desperate relief and all the love in the whole entire world, but that's exactly what his was doing, and he gave a little tug on their hands, he had to get that kid in his arms _right now_.

Donnie cottoned on right away and clambered up into the little infirmary bed with him, curling around Mikey blanket and all. Mikey held him where he could with clumsy hands, blinking through tears of his own that burned and blinded him—so happy it was _painful,_ so relieved to see him it _hurt._

"'m so glad you're here," he said, and it probably didn't make sense out of context, it probably sounded all thick and childish 'cause he was crying like a baby, but he didn't _care._ Donnie's forehead was right up against his, his brother's octopus arms tight around his shoulders and his carapace, and for some reason, he was heavier than Mikey remembered, and a lot bigger; he didn't quite fit against Mikey the way he did before.

But it didn't matter. He was _Donnie._ And just for that, Mikey hugged him even closer, and loved him absolutely and forever.


	5. always, I know

Four days since Mikey's brief, _concussed_ flirtation with consciousness, three days since he was cleared from the infirmary ( _"Okay, Mikey. I think I can let you go now."_ ) and Mikey had _kinda_ thought they were just gonna pretend like none of it had ever happened.

The gibberish and the cuddling and the crying, that is.

He remembered enough of it to be a hundred percent _completely_ _mortified_ , which was a new and uncomfortable feeling—like when sensei made them wear layers of human clothes during their first bitter winters, coats that caught around their shells and sat strangely on their shoulders—and every time Donnie looked at him it was with the _weirdest_ expression; like Mikey had turned the universe upside down just for laughs, and left his brother to figure out a bunch of new laws of motion and physics.

They were _okay,_ though _._ For the most part. They still sparred together at practice and stuff, and sat next to each other at the dinner table, and rolled their eyes in unison when Raph and Leo started arguing over the same stupid thing for probably the ten millionth time.

But… sometimes, Donnie would just… _look_ at him. With that same weirdness. And Mikey didn't know what to _do_ when he did that.

" _Sorry for crying on you and making everything_ really awkward! _Everything's cool, I'm cool, I'm just, like, sorta confused—by my life and the entire world and you, kinda—but I'll figure this out! Promise!"_

Somehow he didn't think that would work. The P-word probably wasn't exactly the charm it used to be.

Then— _three days later,_ out of _nowhere,_ Mikey hadn't even seen it _coming—_ Donnie called him to the lab, with a "hey, I need your help with something," and Mikey fell for that, like an _idiot,_ and now he was cornered _._ He belonged on one of those "what NOT to do" stranger-danger posters.

"We need to talk," Don said, really gently, and Mikey wanted to disappear. This was it. This was when they talked about how much Mikey was messing everything up, because he couldn't seem to click back into place with his brother the way he used to—the way he thought he'd be able to, just slide back into the practice of "Before the Accident," but back then they weren't _buddies,_ and as much as Mikey didn't know how to be around Don anymore, he still _wanted_ to, really really bad. And now Donnie was finally fed up with it—with _him_. And the tentative okayness was over, and it was going to be like before.

His expression must have been telling, because something slow and soft happened to Donnie's face. "Don't look at me like that. I'm not angry."

Which was how Mikey found himself back on the infirmary bed, sitting with his legs dangling over the side, feeling about an inch tall under his big brother's x-ray eyes.

Then Donnie's desk chair squeaked a bit, and Mikey blinked at the weight that dipped the bed as his brother sat next to him. And blinked again, when Donnie reached over to pick up one of his hands. It was small compared to Donnie's, and wrapped up painstakingly in gauze and medical tape; and as he watched, Donnie's fingers curled around his entirely.

"I mean… I _wanted_ to be angry. When Rocksteady almost crushed you, and I had to carry you home. You almost got—really, really badly hurt that time, Mikey. For me. And I wanted to be _furious."_

For a second he _looked_ furious, words notwithstanding, and Mikey shuffled his feet meekly.

"Sorry, Dee."

And he meant it. He didn't mean to scare him—how many times had _he_ been where Donnie was, watching one of his big brothers take a hit meant for him? He _knew_ it was scary, especially in the after, back at home, waiting for them to wake up. And he really was sorry that Don had to be scared like that, but he wasn't sorry he did it, not even a little. Not even with the bruised ribs and bruised brain and bruised everything else he got out of the deal.

He was only a big bro for like a month, but… he sorta understood now.

He wouldn't be as good at it as Leo (and all those times Leo would draw his swords and stay behind to give his little brothers time to get away, steadfast and strong and never once looking back, not even for a second) or Raph (and the fierce compassion that maybe looked like fury when coupled with snapping green eyes, the fierce _wanting_ to take on the whole world because he had so much love to prove) but he would always, always _try._

Try to keep them safe, no matter what.

And in that way, Mikey knew his brothers a little bit better. And he was sorry Donnie had to worry, but he wasn't sorry for anything else.

And Donnie was still being kind of psychic, because a crooked smile was tugging at one side of his mouth, and he gave Mikey a nudge with his shoulder. "Not sorry enough to _never_ do it again, though, right?"

He didn't sound upset—sounded kind of reluctantly amused, actually, if anything—and Mikey found himself smiling back a little, like a knee-jerk reaction. "Right. I always said you were smart." Donnie snorted and shook his head, and Mikey tapped his fingers against his kneepad, summoning courage. Call it morbid curiosity, but he had to know; "Uh—why _aren't_ you mad, Dee?"

"'Cause we made a deal," the purple-banded turtle said, with a shrug, like it was the most obvious thing in the world. "I protect you, and you protect me." And at the probably dumb look on Mikey's face—was that the world exploding, or just his brain?—Donnie frowned without anger, raised one eye-ridge, and added, "What, you thought I'd forget?"

* * *

And the next night, after dinner, Donnie came back to the kitchen with something bundled up in his arms. Mikey took one look and burst out laughing.

It was the dismantled toaster, wrapped together with all its loose parts in an old, oil-stained towel, and Don was looking markedly flustered the longer Mikey giggled. When he managed a "why haven't you _fixed_ that yet?" he got a defensive, "I've been busy, okay?" in response that really only made laugh more.

But when Donnie sat down at the table with the battered-looking, scorch-marked appliance, spreading out the towel and arranging all the pieces, Mikey left the last couple dishes to drown in the sink for a little while, moving over to take the chair next to him. "I can't believe you let me get away with this," Don said after a moment, and Mikey grinned.

"Aww, you weren't hurting anything."

"I set the _kitchen_ on fire!"

Mikey waved one hand grandly. "Accidents are how we learn," he said, in a sub-par impersonation of their father. It coaxed an amused snort of Donnie, at least, and Mikey folded his arms on the table and rested his chin on top to watch.

Donnie tinkered for a moment, looking kind of distracted. Then he glanced sidelong at Mikey, something fleeting and uncertain in his eyes, and said, "Do you want to give me a hand?"

"Uh…" Mikey blinked. "Well—I mean, sure, Dee, but I dunno how much help I'll be."

"I can teach you," he said, and he looked about as nervous as people walking a tightrope probably did, like there was a great big chance Mikey would laugh at him in a mean way, or tell him no. Which was stupid, way stupider than a genius like Don should be allowed, because Don could ask him for literally anything, Don could ask him for the _moon,_ and Mikey's answer would be something along the lines of,

"Sure. Absolutely."

Donnie didn't look up to him anymore—Mikey thought he'd always kinda miss that.

But Donnie _did_ let Mikey pick up a few stray pieces of their poor broken toaster and fit them together, fumbling and clumsy next to Donnie's practiced hands; and his explanations were easy and patient, even when he had to repeat himself, and it all sort of actually starting making sense there by the end—and it was even _really fun_.

When the whole thing was finished, and their test-run toast popped out all golden-brown and perfect, Mikey cheered, and Don rubbed his head fondly.

"Thanks, Mike."

And "thanks" from Donatello usually meant "thanks" for a hundred different things all at once; and Mikey knew this "thanks" was probably less about the toaster, and more about more important things—like promises, and shadow puppets, and bedtime stories, and banana splits.

Mikey knew what he meant. So he smiled warmly, and reached over to hug Donnie around the shoulders as tight as he could.

"Any time, Dee. I mean, what's a kitchen without a toaster?"


End file.
